Just to clear up on the confusion wrought by the other answers, for the future readers of this question: exercises for finger independence DO exist, and some experienced guitarists actually can move their ring finger much more freely than we mortals.
In fact, I came upon this question while googling for 'ring finger exercises'. I'm sure that the original author has done his research by this time, but as an example, here's a page on some guitar exercises: http://resource.takelessons.com/guitar-exercise-strengthening-the-ring-finger-pinky/
Most probably there also are exercises that are not related to any instrument at all and just let anybody improve finger agility and control.
My friend, who isn't even a professional musician but has played classical guitar (by chords) for many years, can move his ring finger practically as good as any other. He has shown me another pretty impressive test for finger agility: from the closed fist, move your pinky up at the lowest joint while keeping it bent otherwise. Then, keeping all other fingers in place, extend the ring finger and straighten it all the way up. (Alternatively, from the ring and pinky straight, try to bend the pinky without moving the ring finger.) Chances are that a non-musician like me won't be able to do it more than halfway through—and my friend can do it all the way.